Improvement in pavements



J. B. SPEED.

Pavements.

Patented Feb. 4, 1879.

l No.V 211,941.

,f f@ if [raven/fol."

Mvf. a7'

METERS. PHDTO-LJTHDGRAPHER. WASHINGTUN, D. C.

UNTTED STATES PATENT OEETcE.

.IAllIES B. SPEED, 0F LOUISVILLE, KENTUCKY.

IM PROVEM ENT IN PAVEMENTS.

Specification forming part of Letters Patent NO. 211,941, dated February 4, 1879; application led November 29, 1878.

To all whom it may concern:

Be it known that I, JAMEs B. SPEED, of Louisville, in the county of Jefferson and State of Kentucky, have invented certain new and useful Improvements in Pavements 5 and I do hereby declare that the following is a full, clear, and exact description of tle invention, which will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters of reference marked thereon, which form a part of this specification.

My invention has for its object the construction of a pavement having a surface formed of bowlders, the foundation of which is made of stone or gravel, mixed with sufficient hy-v draulic cement to form a solid and impermeable bed of hydraulic concrete, on which is laid a stratum of purer hydraulic cement, into the upper surface of which the Cobble-stones are embedded to about half their diameter while.

the concrete is plastic.

In this class of pavements heretofore known the Cobble-stones are laid in sand or gravel, from which they are liable to be detached, making holes in the pavement, or the cobblestones are pressed down into the sand, leavingan irregular surface. In other cases blocks of stone have been laid on a concrete bed formed of various admixtures of tar laid down and smoothed, the base of the stones resting ou the bed, the interstices being lled with tar concrete, which sometimes extends over the face. ln other instances the bed is formed of concrete of which tar forms a constituent, for the purpose of giving an elastic foundation to cobble or other stones laid on the foundation, and then covered by a layer of concrete of similar constitution, which covers and embeds the stones, forming, when finished, a smooth surface. In other cases pieces of broken stone are rolled into the surface of a concrete bed, the surface of the pavement being formed in part of the stone and in part of the interstitial concrete. In other cases concrete and stone pavements have been built up by the application of a solution of lime with dry gravel or coal ashes, and Itosendale or hydraulic cement mixed and sifted into the crevices of thebroken stone, so that the stones shall interlock'between the bed and each other, with this concrete between them, and form a stone and concrete surface.

My invention is distinguished from all those previously known in this, th at it is laid on a bed in which the bottom is made of a cheap yet impermeable mixture of stone and cement, overlaid by a stronger and harder mortar of hydraulic cement, in which the stones are partly embedded before it sets, leaving the surface of Cobble-stones without any surfaceeovering.

The upper stratum of concretebecomes with age as hard as stone, and being firmly connected to each bowlder forms a solid and durable surface to the street.

In the annexed drawings, Figure I is aplan view of the pavement. Fig. Il is a vertical section.

The same letters indicate identical parts.

A is a road-bed, properly graded to receive the pavement. B is the foundation, formed of stone or coarse gravel and sand, mingled with hydraulic cement sufiicient to unite the stones and make a compact and impermeable bed. This is laid down, smoothed, and compacted by rammin g or rolling, and allowed to harden. On this is then laid a coating, C, of, say, two to three inches in thickness of concrete formed of line gravel and sand, mixed with a larger proportion of hydraulic cement, so as to form a plastic surface, in which, while soft, the cobble-stones D are embedded to about the middle of their diameter, and laid so as to form a uniform surface. Sand is then thrown on to fill the interstices What I claim as my invention, and desire to secure by Letters Patent, is.-

Constructing a pavement with a foundation of concrete formed of a mixture of stone, sand, and hydraulic cement, an overlying stratum of concrete formed of hydraulic cement and fine gravel, or fine gravel and sand, and a surface of cobble-stones embedded in the concrete before it hardens, substantially as set forth.

In testimony that I claim the foregoing as my own I aiiix my signature in presence of two witnesses.

JAMES B. SPEED.

lVitnesses:

D. P. HoLLowAY, GEO. F. GRAHAM. 

